Before being cooked, the cheese used for melting contains long-chain protein molecules , that is, made up of a large number of atoms. These molecules are usually curled up in a fatty mass. When the cheese is heated, the fats and proteins mix to form a compact group of fibers that is easy to break . For example, when someone sticks a fork into melted cheese fresh from the oven, the silverware acts like a comb, turning the strings into grooves. In essence, it would be something like extracting a thread from a ball of wool.
This process can be reproduced in many other materials that contain long chain compounds, for example those that come from carbon chemistry either naturally or by synthesis. This is the case of polymers used, for example, in the manufacture of plastic bags. If you do the test and heat one of these bags, you will find that it looks very similar to melted cheese: it is also elastic and can break down into sticky threads.
What's more, some experts propose that the length these threads acquire before breaking can be used to measure the amount of protein molecules that cheese contains. It would be like seeing a chemical phenomenon live.
